1. Field of the Invention
The present invention relates to a transmission line for a capacitive coil and, more particularly, to a transmission line for a capacitive coil that realizes distributed capacitance so as to minimize loss of power in a power cable.
2. Description of the Related Art
As means for pollution prevention and reduction of reliance on petroleum energy, electric vehicles powered by electricity and hybrid vehicles powered selectively by electricity or internal combustion engines have been developed.
Currently, such an electric vehicle and (plug-in) hybrid vehicle should be connected to external power supply equipment through a plug or the like for a longtime to charge batteries and may run only a limited distance on a single charge.
As such, in recent years, electric vehicles using electromagnetic induction have attracted wide attention as an alternative to electric vehicles using batteries.
Electric vehicles using magnetic induction require power feeding roads or rails supplying electricity. Such an electric vehicle or electric train need only run on a power feeding road to draw power. That is, while travelling on a power feeding road, the electric vehicle may draw high-frequency power to drive through electromagnetic induction between power supply lines and power collection equipment installed in the vehicle.
Supplying power to a power feeding road requires a large number of inverters. As inverters become expensive with increasing capacity, efficient electric wiring is needed so that each inverter supplies a small amount of power.
When power supply lines become long, increased self-inductance thereof results in high resistance, hindering flow of current. Hence, supply of a target amount of current necessitates a voltage increase, causing a cost increase. To solve problems due to the length of power supply lines, a large number of resonant capacitors are installed to compensate for a voltage due to inductance in the power supply lines.
Installation of a large number of resonant capacitors may entail difficulty of capacitor arrangement and wiring complexity, and hence the installation process may be delayed and the installation time may be significantly increased. Further, resonant capacitors need additional space according to size thereof and expenses increase according to number thereof.
In Patent document 1 below, a transmission line type component is proposed that may be used as a high-frequency electronic circuit element. The transmission line type component is a single capacitor component, which may be used a high-frequency decoupler in an electronic circuit. The transmission line type component is viewed as a lumped element that is to be selected in consideration of wavelength.
In Patent document 2 below, a Helmholtz type sample coil is used specifically for design of an NMR probe.